An example of such a machine for centering lenses is described and shown in the document EP-A-0 206 860. This machine mainly comprises a horizontal planar surface, such as for example a flat screen, on which rests a lens blank, and a device for mounting an adapter on the blank, the device being mounted to be movable between an adapter-loading position and an adapter-mounting position.
The device for mounting the adapter is for example constructed in accordance with the teaching of the patent application FR-A-2,613,268 and comprises a housing in which is slidably mounted a shaft whose end is arranged to receive an adapter.
When the mounting device is in position for mounting the adapter, the axis of the slidable shaft is coincident with a reference axis of the centering machine which is perpendicular to the blank support.
The user of such a machine first of all effects a precise geometrical positioning of the lens blank with respect to the reference axis, then, in a second step, brings the adapter-mounting device to the mounting position, and lastly effects the mounting proper by causing a vertical downward sliding of the slidable shaft the end of which had been loaded with an adapter.
It has been found that the mounting device which equips such a machine is not very aesthetic and is particularly large.